Process of making steel



(N0 Mael. R. P. LUDLOW.

PROCESS OF MAKING STEEL. No.-412, 768. Patented Oct. 1889.

N. PETERS, Photo-Lithographer, Washington. I)v C.

NITED STATES PATENT Enron,

PROCESS OF MAKING STEEL.

SPECIFICATION forming part of Lettersfatent No. 412,768, dated October 15, 1889. Application filed January 23, 1889. $erial No. 297,296. (No specimens.)

To all whom it may concern:

Be it known that I, RODNEY F. LUDLOW, a

citizen of the United States, residing at Springfield, in the county of Clark and State of Ohio, have invented certain new and useful Improvements in the Process of Making Steel,

of which the following is a specification, reference being had therein to the accompanying drawings.

This invention relates to an improved method of decarbonizing iron and liberating the impurities contained therein While in .a molten state, for the purpose of rendering the iron in condition to be recarbonized by fluxing therewith some recarbonizing agent,

to convert it into malleable iron or wroughtiron, or to convert it into steel.

Before entering into a detailed description of my improved method, I desire to embody herein certain acknowledgments of the state of the art as hereinbefore developed, for the purpose of more clearly distinguishing my invention therefrom, to the end of more strictly complying with the statute relative to distinguishing the old from the new.

, Prior to my invention atmospheric air has been introduced vertically through a mass of molten iron; has been introduced or forced horizontally into the mass; has been intro; duced at anangleand into the deepest part of the metallic bath; has been introduced tangentially to and into such mass or bath below the surface thereof, and has been directed from above at an angle to and against the surface of the molten mass; in short, that a molten mass or metallic bath has been acted upon for the purpose of eliminating the imp urities contained therein and decarbonizing it by atmospheric air projected through, among, and in contact' therewith, and, finally, that such mass or bath of iron has been subjected to air-currents by violently agitating limited portions only of such mass, while the greater portion was held in a state of comparative quiescence, in such a manner as to bring every portion repeatedly within the area of such violent agitation. My invention differs from each and all of these acts or methods in important, economic, and practical particulars; and, briefly stated, may be said to consist, first, in disturbing the entire mass of molten iron with practical uniformity by contion, and, secondly, in fusing with the mass.

of metal so treated a quantity of some recarbonizing agent by mixing such agent therewith, after the impurities have been eliminated from the mass and the iron brought to a decarbonized state.

In the annexed diagrams, Figures 1 and 2,1 have illustrated baths of molten metal and air-currents acting upon them insubstantial accordance with my invention.

I will now proceed to describe my method more in detail and the manner of conducting the same. The molten iron is preferably run off from any of the known melting-furnaces or otherwise removed from such furnaces and placed in a vessel constructed or lined with refractory material to enable it to withstand the heat of the metal. The depth and other dimensions of this vessel, which may be termed the converter-vessel, will vary with the amount of metal contained in each bath to be decarbonized, &c., and possibly according to local conditions and the desire or choice of the practicer of the method. As it is pre ferred to remove the dross, scoria, slag, or

other impurities that may be found to have accumulated on the surface of the bath prior to the introduction of the recarbonizin g agent, I recommend that the converter-vessel be constructed-with an opening at the side above the level of the bath, through which suitable skimming-tools may be introduced forremoving such impurities. These remarks apply to instances in which the converter-vessel at its upper edge is too high from the surface of the bath to render the skimming operation convenient from over the edge of the converter. After the molten metal has been placed in the converter-say to the extent of a ton-I employany suitable apparatus for directing airourrents upon or against and at an angle to the surface of the bath, and I vary the place of contact between such currents and said surface, so as to extend the places of such contact across practically the entire surface, embracing more or less of the width of such surface, preferably from one-half to five-eighths or three-fourths thereof, measuring from one side of the converter-vessel toward the other and crosswise to the line of the air-blasts. If the places of contact at the commencement of the operation are established near to the side of the converter farthest from the side from which the currents proceed, then the metallic bath will more quickly start in a motion than if such places of contact are first established nearer to the side of the converter from which the currents proceed, the quickness with which the mass of metal responds in motionto the action of the currents growingless and less as the places of contact grow nearer and nearer to the blast or current side of the converter. I also prefer that the angles between the air-currents and the surface shall vary as the places of contact are varied, approaching more nearly to a right angle as such places of contact approach the current side of the vessel, though this variance in angle is by no means a necessity to the successful operation of the method. hen the currents are turned on and the metal begins to respond to them by assuming motion, the places of contact are changed by changing the diree-. tion of the air-currents or varying the position of the place from which they proceed, and I prefer to constantly effect this change and to not allow the currents to strike a given breast on the surface of the bath more than a minute or two, thus keeping up a constant change in the places of such contact. \Vhen the places of contact have proceeded across the surface of the bath in a breast of the desired width, they are then reversed and the places of such contact continued step by step back in the opposite direction until such length of timeusually from eight to eleven minutes per ton-shall have elapsed to bring to the surface the contained impurities and to liberate or consume the carbon contained in the bath.

One object in changing the places of contact bet-ween the air-currents and the surface of the bath progressively back and forth or across such surface is to insure reaching all of the impurities as the particles or quantities thereof come to the surface at different places, as a result of the general and. practically uniform disturbance of the entire mass, of which no portion is sufficiently quiescent for the retention of any essential portion or particle of the impurities. Again, as the places of contact proceed in the direction of the far side of the converter, the impurities which have come to the surface are hastened to said side, where they more orless accumulate.

I have said that the breast of air-currents was preferably less than the width of the surface of the bath. I prefer this, as it results in giving the metal a rotary motion, which, if not constant, is more or less intermediate or spasmodic, resulting in a more thorough agitation of the entire mass, in consequence of the conflict of metallic currents between the rotary and tumbling tendencies imparted by the air.

hat is here described is based upon what has been ascertained by tests on a large and practical scale of commercial capacity. The product is either metallic or wrought-iron of great textile strength and ductility, or steel of like strength and fineness of texture.

\Vhile any recarbonizing agent may be employed, I prefer to use what is known as spiegeleisen, and to apply it to the bath in a powdered state by throwing a sufficient quantity thereof into the converter-vessel after the impurities have been skimmed from the surface.

I hereby disclaim as a part of myimproved method herein set forth all those steps and that treatment of the iron which occur in redueing it to a molten state and conducting the same into the converter, as the method involved in these steps forms an important part of the subject-matter of application filed by me December 18, 1888, Serial No. 293,983, under the title of method of manufacturing iron and steel.

Having thus fully described my invention, what I claim as new, and desire to secure by Letters Patent, is-

1. The herein-described method of decarbonizing iron and liberating the impurities contained therein, the same consisting in disturbing and putting in practically uniform motion the essential mass of a bath of molten iron by constantly varying the place of contact therewith, of air currents projected against and upon the surface thereof at an angle thereto, and in maintaining this operation until the contained carbon and impurities are liberated and the latter collected on the surface of the bath.

2. The herein-described method of decarbonizing iron and liberating the impurities contained therein, the same consisting in disturbing and putting in practically uniform motion the entire mass of a bath of molten iron by directing air-currents upon and against the surface thereof at an angle thereto, and in constantly varying the places of contact back and forth across said surface, in maintaining this operation until the contained carbon and impurities are liberated from the iron, in removing the collected impurities, and in uniting with the bath in this condition some recarbonizing agent in quantities to suit the product sought.

In testimony whereof I affix my signaturein presence of two witnesses.

RODNEY F. LUDLOIV.

Witnesses:

M. T. BURNHAM, WARREN HULL. 

